@fanbaby: Huh? Category theory has been a huge influence on computer science for decades already, it's hardly a new thing, let alone a Microsoft thing. Although Erik Meijer's work at Microsoft has done a lot to popularize some of the ideas.
After a quick search I see some references going back to 1975. That was kind of surprising. I thought the real first implementation was not until 1990's in Haskell (monads). Please enlighten us further on the history, if you know. Thanks!